In-Space Manufacture of Storable Propellants

Transcription

1 In-Space Manufacture of Storable Propellants John S. Lewis Deep Space Industries NIAC PI Meeting, Seattle, 28 October 2015 SBAG, JHU, 29 June 2016

2 In-Space Manufacture of Storable Propellants Most of the Earth-launch mass for deep-space missions is propellant especially for return missions Propellant manufacture in space enables retrieval of large masses of native materials and products Cryogenic propellants require large masses of refrigeration/ liquefaction equipment, tankage (for LH2!) and insulation Storable fuels and oxidizer can be made using only water and CO2 Heating C-type asteroids releases abundant water and CO2 We are studying co-production and use of storable propellants

3 Storable Propellant Production Roadmap 1. Extraction of water for use as STP propellant 2. Extraction of water and CO2 for synthesis of storables 3. Purification of gases: elimination of sulfur and toxic gases 4. Electrolysis of water to generate H2 and O2 gases 5. Catalytic reaction of H2 and CO2 to make dimethyl ether, etc. 6. Fuel cell reaction of H2 with O2 to make H2O2 + energy 7. Use of DME/H2O2 propellant for moving large masses

4 What do we do where? Full-scale storable propellant manufacture requires large energy input and complex handling Extraction of water alone can be done relatively simply and at lower temperatures to minimize sulfur gas production Water is an ideal fluid for Solar Thermal Propulsion (STP) STP can return large masses of raw materials to Highly Eccentric Earth Orbit (HEEO): staging ground; fuel depot First mission extracts water for STP retrieval of large masses of raw C-type asteroid material to HEEO

5 Progress on initial retrieval mission 1. Developed a mineralogical model of CI chondrites 2. Thermodynamic modeling of volatile-element release from heated asteroid mineral assemblages 3. Energy and power requirements for H2O & CO2 extraction 4. Development of a scheme for H2O and CO2 transportation 5. Showed value of STP using water vapor exhaust; showed gross inferiority of schemes seeking high Isp by using H2 instead of water 6. Applied Tsiolkovskii s optimum Isp theory to validate water

6 Decomposition Pressures of Minerals

7 Sulfur Dioxide Pressures, CI chondrite at 800 K (contours of log10 of SO2 pressure, atm)

8 Sulfur Dioxide Pressures, CI at 1000 K

9 Storable Propellants: HEEO Operations Experiment on extraction of volatiles from carbonaceous asteroids: strong heating to maximize volatile extraction of H, C, O, S, and N (~40% of total asteroid mass) Develop processes for separation of volatiles and purification of water, especially sulfur removal (poisons many processes) Refine DME and H2O2 production schemes and adapt them to use H2O and CO2 retrieved to HEEO from C asteroids HEEO becomes the site of propellant production for use in LEO, GTO, GEO, and deep-space missions (Mars, PhD, asteroids)

10 Progress on Propellant Manufacture and Storage 1. Down-selected numerous schemes for H2O2 and DME (etc.) manufacture for co-production compatibility 2. Demonstrated ability to use only H2O and CO2 as starting materials for propellant manufacture 3. Developed a kinetic model for H2O2 storage showing decomposition rates as low as 10-5%/yr at reduced T 4. Identified and proposed solutions to problems of catalyst poisoning by sulfur gases in both fuel production and Mond processing of metals 5. Showed Isp of DME/H2O2 is 300 s; verified that each 2% of H2O2 dilution lowers Isp by only 0.6%

11 Condensates in the H2O-CO2 System

12 Decomposition Rate of 90% H2O2 in Al Tanks

13 Vapor Pressures of H2O2 Solutions